The Alfa weighs just 20lbs, yet supports riders up to 24 times its weight. It’s mostly cardboard and 100% recycled materials. It uses a belt-driven pedal system that makes it maintenance free. And, maybe best of all, it’s projected to be manufactured at about $9 to $12 per unit (and just $5 for a kids version), making it not only one of the most sustainable bikes you could imagine, but amongst the cheapest, depending on the markup. Here’s a pic and video of the cardboard bike: